Chan Lap Ki
Department of Biological Anthropology and Anatomy, Duke University Medical Center, Durham, NC 27710, USA.
Am J Phys Anthropol. 2008 Jul;136(3):265-77. doi: 10.1002/ajpa.20800.
Hominoids and lorines are assumed to possess greater shoulder mobility than other primates. This assumption is based on morphological characteristics of the shoulder, rather than on empirical data. However, recent studies have shown that the glenohumeral joint of hominoids is not more mobile than that of other primates (Chan LK. 2007. Glenohumeral mobility in primates. Folia Primatol (Basel) 78(1):1-18), and the thoracic shape of hominoids does not necessarily promote shoulder mobility (Chan LK. 2007. Scapular position in primates. Folia Primatol (Basel) 78(1):19-35). Moreover, lorines differ significantly from hominoids in both these features, thus challenging the assumption that both hominoids and lorines have greater shoulder mobility. The present study aims to test this assumption by collecting empirical data on shoulder mobility in 17 primate species. Passive arm circumduction (a combination of glenohumeral and pectoral girdle movement) was performed on sedated subjects (except humans), and the range measured on the video images of the circumduction. The motion differed among primate species mostly in the craniodorsal directions, the directions most relevant to the animal's ability to brachiate and slow climb. Hylobatids possessed the highest craniodorsal mobility among all primate species studied. However, nonhylobatid hominoids did not have greater craniodorsal mobility than arboreal quadrupedal monkeys, and lorines did not have greater craniodorsal mobility than arboreal quadrupedal prosimians. Nonhylobatid hominoids and lorines had similar craniodorsal mobility, but this was due to a longer clavicle, more dorsal scapula, and lower glenohumeral mobility in the former, and a shorter clavicle, less dorsal scapula, and greater glenohumeral mobility in the latter. This study provides evidence for the reexamination of the brachiation, slow climbing, and vertical climbing hypotheses.
类人猿和懒猴被认为比其他灵长类动物具有更大的肩部活动度。这一假设基于肩部的形态特征，而非实证数据。然而，最近的研究表明，类人猿的肩肱关节活动度并不比其他灵长类动物更大（Chan LK. 2007. 灵长类动物的肩肱关节活动度。《灵长类动物学杂志》（巴塞尔）78(1):1 - 18），并且类人猿的胸廓形状不一定能促进肩部活动度（Chan LK. 2007. 灵长类动物的肩胛骨位置。《灵长类动物学杂志》（巴塞尔）78(1):19 - 35）。此外，懒猴在这两个特征上与类人猿有显著差异，因此对类人猿和懒猴都具有更大肩部活动度这一假设提出了挑战。本研究旨在通过收集17种灵长类动物肩部活动度的实证数据来检验这一假设。对镇静状态下的受试对象（人类除外）进行被动手臂环转（肩肱关节和肩带运动的组合），并在环转的视频图像上测量范围。灵长类物种之间的运动在颅背方向上差异最大，这些方向与动物的臂行和缓慢攀爬能力最为相关。在所有研究的灵长类物种中，长臂猿科动物具有最高的颅背活动度。然而，非长臂猿科类人猿的颅背活动度并不比树栖四足猴子更大，懒猴的颅背活动度也不比树栖四足原猴更大。非长臂猿科类人猿和懒猴具有相似的颅背活动度，但这是由于前者锁骨较长、肩胛骨更靠背且肩肱关节活动度较低，而后者锁骨较短、肩胛骨靠背程度较低且肩肱关节活动度较大。本研究为重新审视臂行、缓慢攀爬和垂直攀爬假说提供了证据。
